JPH0211387Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Technical field of invention] The present invention relates to a paper feeding device.

[Technical background of the invention and its problems]

Examples of paper feeding devices include those used in electronic copying machines. This is a paper accommodating section that stores a plurality of sheets of paper and is equipped with a sheet ejecting member, for example, a separating claw, that presses the corner of the leading edge of the sheet in the feeding direction in order to sequentially send out the stored sheets one by one. A paper feeding member such as a paper feeding roller that comes into contact with the edgemost layer of paper stacked and stored in this paper storage unit, and a stepping motor that drives this paper feeding roller to feed out the paper sheets one by one one by one. and a drive control system that controls the driving of this stepping motor.

By the way, in the case of feeding paper through the separation claw, when the paper feed roller is driven, the feeding of the paper is first regulated by the separation claw, and the middle part of the paper is bent upward and deformed, and the paper is deformed to some extent. By the way, the paper is separated from the separation claw and sent out.
When paper is fed in this manner, the feeding force exerted on the paper by the paper feeding roller until the paper leaves the separating claw is greater than the feeding force thereafter. This is because deforming the paper requires energy. The change in the feeding force at this time increases almost gradually from the time of startup to the time of separation, as shown in FIG. 1, and then becomes steady.

However, in the past, no consideration was given to such changes in the feeding force, and the stepping motor rotor ended its accelerated operation and transitioned to steady operation before the paper was released from the separation claw. was. This has led to problems in that the driving efficiency of the stepping motor is reduced, and in some cases synchronous rotation is no longer possible due to overload caused by deformation of the paper.

[Purpose of invention]

The present invention has been developed in view of the above circumstances, and aims to provide a paper feeding device that can improve the driving efficiency of the stepping motor and also provide stable paper feeding. be.

[Summary of the idea]

The present invention includes a paper storage unit equipped with a single sheet feeder, a paper feed member that comes into contact with the outermost layer of sheets stacked and stored in the paper storage unit, and a paper feed member that drives the paper feed member to A stepping motor that sequentially feeds sheets one by one, and a drive control system that accelerates and drives at least the stepping motor until the sheets fed by the sheet feeding member are separated from the sheet feeding member. It is characterized by comprising:

[Example of idea]

Embodiments of the paper feeding device of the present invention will be described below with reference to the drawings.

Fig. 2 is a schematic perspective view showing an embodiment of the paper feeding device of the present invention, and Fig. 3 shows a drive system for the first paper feeding member and the second paper feeding member in the paper feeding device shown in Fig. 2. An explanatory diagram, FIG. 4 is an explanatory diagram showing the drive system of the feeding member and alignment conveyance member in the paper feeding device shown in FIG. 2,
Fig. 5 is a sectional view of the paper storage section, Fig. 6 a, b, c
7 is a detailed explanatory diagram of the single sheet feeding member, FIG. 7 is a detailed explanatory diagram of other sheet feeding members, FIG. 8 is a block diagram showing the stepping motor drive control system, and FIG. 9 is the stepping motor. FIG. 10 is an explanatory diagram showing the torque-speed characteristic curve of the stepping motor.

The paper feeding device shown in the figure includes a manual guide 1 for manually feeding paper, a first paper storage section (e.g., a first paper feed cassette 2) containing paper, and a second paper storage section (e.g., a first paper cassette 2) containing paper. Two paper feed cassettes 3 are removably arranged in a copying machine main body 4. A feeding member, for example, a pair of manual feeding rollers 5, 5, which feeds out manually fed paper, is disposed in the inner part of the manual feeding guide 1 in contact with the manual feeding guide 1. Also, the first
A first paper feed member, for example, a first paper feed roller 6, which sequentially frictionally feeds the uppermost sheet of paper P stored in the paper feed cassette 2, is arranged so as to be able to rotate integrally with the shaft 6A. Further, a second paper feed member, for example, a second paper feed roller 7, which sequentially frictionally feeds the uppermost layer of paper P stored in the second paper feed cassette 3, is arranged so as to be able to rotate integrally with the shaft 7A. ing. Further, an alignment conveyance member, for example, a pair of registration rollers 8, 8, aligns and conveys the paper fed by the manual feed roller 5, the first paper feed roller 6, or the second paper feed roller 7. are placed in contact with each other. Note that paper guides 9A, 9B, and 9C are provided between the rollers 5, 6, and 7 to the registration roller 8, as shown in FIG.

Next, a drive system for the first paper feed roller 6 and the second paper feed roller 7 will be explained based on FIGS. 2 and 3. A first drive gear 11 is attached to one end of the shaft 6A via a first one-way clutch 10A. The first one-way clutch 10A is connected to the first drive gear 11.
Only the clockwise rotation of the shaft 6A is transmitted to the shaft 6A. A second one-way clutch 10B is connected to one end of the shaft 7A.
A drive gear 12 is attached. The second one-way clutch 10B is configured to transmit only clockwise rotation of the second drive gear 12 to the shaft 7A. The copying machine main body 4 is provided with a first stepping motor 14, and a pinion gear 15 is attached to the motor shaft of the stepping motor 14. Between this pinion gear 15 and the first drive gear 11, two idle gears 16A, 1
6B, and one idle gear 16C is arranged between the pinion gear 15 and the second drive gear 12, and as shown in FIG. 3, the pinion gear 15 is rotated counterclockwise. Then, the first paper feed roller 6 is
Only the pinion gear 15 rotates clockwise, and the pinion gear 15 rotates clockwise.
When rotated clockwise, the second one-way clutch 10B and idle gear 16C are rotated.
Only the paper feed roller 7 rotates clockwise.

Next, a drive system for the registration roller 8 and the manual feed roller 5 will be explained based on FIGS. 2 and 4.
An idle pulley 19A is provided at one end of the shaft 5A, which rotates integrally with the lower manual feed roller 5 shown in the figure, via a third one-way clutch 18A. The third one-way clutch 18A is adapted to transmit only the counterclockwise rotation of the idler pulley 19A to the shaft 5A. Further, a drive pulley 19 is connected to one end of the shaft 8A which rotates integrally with the lower registration roller 8 shown in the figure via a fourth one-way clutch 18B.
B and an idle gear 20A are provided. The drive pulley 19B is the idle gear 20A.
It is configured to rotate in unison with the
The fourth one-way clutch 18B is adapted to transmit only the counterclockwise rotation of the idle gear 20A to the shaft 8A. A belt 22 is crossed between the idle pulley 19A and the drive pulley 19B, and a pinion gear 20B attached to the motor shaft of a second stepping motor 21 is meshed with the idle gear 20A. As shown in FIG. 4, when the pinion gear 20B is rotated clockwise, only the lower registration roller 8 is driven counterclockwise by the action of both one-way clutches 18A and 18B, and the pinion gear 20B is rotated counterclockwise. When rotating counterclockwise, only the lower manual feed roller 5 is driven counterclockwise.

Here, the configuration of the paper storage section will be explained. Since the two paper feed cassettes 2 and 3 have approximately the same construction, FIG. 5 shows a cross section of one of them. This is because a backup plate 25 biased by a spring 24 is provided at the bottom of the cassette body 26, and when the paper P is placed on the backup plate 25 and installed in the copying machine body, the top layer of paper is removed. It is adapted to come into contact with the first paper feed roller 6.
A corner portion of the leading end of the cassette main body 26 in the paper feeding direction (left side in the fifth figure) is provided with the paper P.
A sheet-unloading member, for example, a separation claw 27, which achieves sheet-unloading (feeding out sheets one by one from the cassette main body 26) by pressing the corner of the leading end (on the left side in the fifth figure) (Details are shown in Figure 6a). In the case of feeding paper through such a separating claw 27, when the first paper feeding roller 6 is driven, the paper P is first regulated by the separating claw and deforms as shown in FIG. 6b. When the paper P is deformed to some extent, as shown in FIG. 6c,
will be separated from the separating claw 27 and sent out. Incidentally, the feeding force exerted on the paper P by the first paper feeding roller 6 until the paper P is separated from the separation claw 27 is greater than the feeding force thereafter. This is because deforming the paper P requires energy. Therefore, in the drive control system of the first stepping motor 14 that drives the first and second paper feed rollers 6 and 7, the time required for the drive control system of the first stepping motor 14 to drive the first and second paper feed rollers 6, 7 is relatively low until the paper P leaves the separating claw 27. The first stepping motor 14 is controlled so as to obtain a large torque (details will be described later). Note that the member for taking out one sheet of paper is not limited to the separating claw 27 fixed to the cassette body as shown in FIG. 6a, but for example, as shown in FIG.
It is also possible to employ a movable pawl 28 that can be moved in the direction of the arrow X shown in FIG. 7 using its own biasing force using the fixing portion 28A to the movable pawl 28 as a fulcrum.

Next, the first and second stepping motors 1
A drive control system for controlling the drives of the components No. 4 and 21 will be explained. In general, a stepping motor operates the rotor one step at a time by sequentially switching DC current through each phase winding of the stator.
It rotates at a step angle unique to that stepping motor. In order to drive such a stepping motor, as shown in Fig. 8, direct current is sequentially switched to flow through each phase winding of the stator of the stepping motor (such switching is hereinafter referred to as excitation phase switching). ), a DC power supply 31 that inputs a voltage to be applied to the stepping motor to the drive circuit 30, and a pulse that is used as a reference for switching the excitation phase to the drive circuit 30. The drive control system 3 is controlled by the oscillator 32.
3, and the first stepping motor 14 and the second stepping motor 21 are each provided with the drive control system 33. The drive circuit 30 stores, for example, a plurality of excitation phase switching times necessary to drive a stepping motor by a desired amount, and counts clock pulses input from the oscillator 32 to count a predetermined excitation phase switching time. When the motor is turned up, an excitation phase switching pulse is output to switch the excitation phase, and the excitation phase is sequentially switched from start to stop to drive the stepping motor by a desired amount. Note that by changing the switching direction of the excitation phase, forward and reverse rotation of the rotor of the stepping motor can be controlled, and by changing the excitation phase switching time, the rotation speed and output torque can be controlled.

In particular, in the drive control system 33 of the first stepping motor 14, as described above, the first stepping motor 14
drive control. In other words, the torque of the stepping motor shown in FIG.
From the speed characteristic curve (T on the vertical axis means the output torque of the rotor of the stepping motor, PPS on the horizontal axis corresponds to the rotor speed and means the number of excitation phase switching pulses given per second) As is obvious, the longer the excitation phase switching pulse interval time (the lower the rotor speed), the greater the torque that can be obtained, so in order to efficiently perform work that requires a large torque, it is necessary to obtain a relatively large torque. It is desirable to drive a stepping motor in a range. Furthermore, in general, when driving a stepping motor, a starting torque is required for the load, so the rotation of the rotor is controlled to be gradually accelerated and then shifted to a desired steady rotation. Therefore, if the period after the stepping motor is started until the paper P leaves the separation claw 27 is at least the acceleration period of the rotor, and then the rotor shifts to steady rotation, when the paper P leaves the separation claw 27, A large torque can be efficiently applied to P. In order to do this, _the excitation _phase switching _time is gradually shortened within the _acceleration section E as _shown in _FIG . ₇
> t ₈ > t ₉ ), and the drive circuit 30 is configured to set each excitation phase switching time (t ₁ ) so that the subsequent phase switching time t _c is constant.
~t _c ).

Note that the stepping motor is operated in the region (self-starting region) in which it can respond to starting, stopping, and reversing in synchronization with the signal based on the excitation phase switching pulse, that is, the region surrounded by the coordinate axes and the torque-speed characteristic curve in Fig. 9. If the accelerated operation is performed, the synchronization will not be lost even if the load acting on the pulse motor fluctuates due to differences in the stiffness of the paper or errors in the deformation of the paper until it is released from the separating claw, and a particularly stable feeding can be achieved. You can do paper.

Next, the operation of the paper feeding device will be explained.

When feeding paper from the first paper feeding cassette 2, by driving the first stepping motor 14 in the third counterclockwise direction in the figure, this rotation is caused to rotate through the idle gears 16A, 16B to the first stepping motor 14. The first paper feed roller 6 is further rotated in the third clockwise direction in the figure by the action of the first one-way clutch 10A. Further, when feeding paper from the second paper feeding cassette 3, by driving the first stepping motor 14 clockwise in the third figure, this rotation is transferred to the second drive gear via the idle gear 16C. 12, and the second paper feed roller 7 is rotated in the third clockwise direction by the action of the second one-way clutch 10B. In this manner, feeding from the first paper cassette 2 or the second paper cassette 3 can be selected by rotating the first stepping motor 14 in the forward and reverse directions. Also, the first
When the stepping motor 14 is driven, the paper P is separated from the separating claw 2 after the stepping motor is started.
Since the rotation is controlled to be at least gradually accelerated from 7 to detachment, and then to steady rotation, a large torque can be efficiently applied to the paper P when the paper P is detached from the separation claw 27. It is possible to feed paper stably and efficiently.

Further, when feeding a sheet manually fed through the manual feed guide 1, by driving the second stepping motor 21 in the fourth counterclockwise direction in the drawing, this rotation is caused to flow through the belt 22. The rotation is transmitted to the idle pulley 19A, and the manual feed roller 5 on the lower side in the fourth figure is rotated counterclockwise in the fourth figure by the action of the third one-way clutch 18A.
Further, when the paper fed from the first paper cassette 2 or the second paper cassette 3 or the paper manually fed is conveyed by the registration roller 8, the second stepping motor 21 The fourth
By driving clockwise in the figure, this rotation is transmitted to the idle gear 20A, and further, by the action of the fourth one-way clutch 18B, the fourth registration roller 8 on the lower side in the figure is rotated in the fourth counterclockwise direction in the figure. It is done by being done. In this manner, driving of the registration roller 8 or driving of the manual feed roller 5 can be selected by rotating the second stepping motor 21 in the forward and reverse directions.

It should be noted that the above embodiment is just an example, and it goes without saying that each member may be replaced with another member having the same function.

[Effect of idea]

As is clear from the above explanation, the paper feeding device of the present invention has excellent effects such as being able to improve the driving efficiency of the stepping motor and also being able to perform stable paper feeding. It is.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing changes in feeding force during paper feeding, FIG. 2 is a schematic perspective view showing an embodiment of the paper feeding device of the present invention, and FIG. 3 is an illustration of the paper feeding device shown in FIG. 2. FIG. 4 is an explanatory diagram showing the drive system of the first paper feeding member and the second paper feeding member; FIG. Figure 5 is a sectional view of the paper storage section, Figure 6a,
b, c are detailed explanatory diagrams of the sheet single sheet feeding member, FIG. 7 is a detailed explanatory diagram of other single sheet sheet feeding members, and FIG.
The figure is a block diagram showing the drive control system of the stepping motor, and Figure 9 shows the torque of the stepping motor.
FIG. 10 is an explanatory diagram showing the speed characteristic curve, and FIG. 10 is an explanatory diagram showing the accelerating operation state of the stepping motor. 2...First paper storage section, 3...Second paper storage section, 6...First paper feeding member, 7...Second paper feeding member, 14...First stepping motor, 33
...Drive control system.

Claims (1)

[Claims for Utility Model Registration] (1) Paper accommodating sections 2 and 3 equipped with single sheet ejecting members 27 and 28, and the outermost layer of sheets stacked and accommodated in these paper accommodating sections 2 and 3. a stepping motor 14 that drives the paper feeding members 6 and 7 to sequentially feed out the paper sheets one by one; and a single paper feed member 2.
7 and 28 act on the paper fed out by the paper feeding members 6 and 7, and a drive control system 33 that causes the stepping motor 14 to accelerate and drive. (2) The drive control system 33 is characterized in that the stepping motor 14 is accelerated in a region where the stepping motor 14 can respond by starting, stopping, and reversing in synchronization with an external signal. A paper feeding device according to claim 1 of the utility model registration claim.